James Rosenwald, a veteran Los Angeles money manager, set up shop in a low-income neighborhood in Nevada to tap a lucrative tax break considered off limits to most Wall Street firms. Dalton Investments, the hedge fund firm he cofounded with childhood friend Steven Persky, took a series of steps to establish itself in an opportunity zone in Las Vegas, according to an October regulatory filing. Opportunity zones, created in 2017 under then-President Donald Trump’s tax overhaul, offer relief from taxes on certain capital gains to those who invest in distressed communities.